[Bug target/69401] gcc 5.3.0/6.1.0 on microblaze: internal compiler error: in gen_reg_rtx, at emit-rtl.c:1027

["thomas dot petazzoni at free-electrons dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69401

--- Comment #4 from Thomas Petazzoni <thomas.petazzoni@free-electrons.com> ---
Any input?

I'm facing a similar problem with the gpsd software: on gcc 6.x and gcc 7.x,
one file fails to build with an ICE:

rtcm2_json.c: In function 'json_rtcm2_read':
rtcm2_json.c:258:1: internal compiler error: in gen_reg_rtx, at emit-rtl.c:1026

You need the combination of -O2 and -fPIC for the bug to appear. If either -O2
or -fPIC are omitted, the builds works fine:

gpsd-3.16$ microblazeel-buildroot-linux-uclibc-gcc -fPIC -c -x c rtcm2_json.os 
gpsd-3.16$ microblazeel-buildroot-linux-uclibc-gcc -O2  -c -x c rtcm2_json.os 
gpsd-3.16$ microblazeel-buildroot-linux-uclibc-gcc -O2 -fPIC -c -x c
rtcm2_json.os 
rtcm2_json.c: In function 'json_rtcm2_read':
rtcm2_json.c:258:1: internal compiler error: in gen_reg_rtx, at emit-rtl.c:1026
 }
 ^
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://bugs.buildroot.net/> for instructions.

I'll attach rtcm2_json.os (preprocessed source code) to ease reproduction of
the build problem.